Night vision goggles (NVG) consist of four major components: 1) an Objective Lens Assembly (OLA), 2) an Image Intensifier (I2) tube, 3) NVG control electronics with battery, and 4) an Eyepiece Lens Assembly (ELA). The objective lens assembly images the outside infrared (IR) scene (up to 900 nm in the optical spectrum) onto the Image Intensifier tube. The Image Intensifier tube converts the IR image to a visible image that is green color at ˜543 nm from the I2 tube phosphor screen. The eyepiece lens assembly then relays the green image to the observer's eye. All these components are integrated into a mechanical housing. Each NVG's Field of View (FOV) is determined principally by its OLA and ELA, while the NVG's resolution is determined by the combination of the OLA, ELA, and the I2 tube.
Currently, the majority of typical NVG has a limited circular FOV of 40°. Attempts to further increase the FOV without compromising resolution are restricted by general optics principles. These optics principles dictate that having both a WFOV along with high resolution can not be obtained simultaneously from an optical NVG system containing modern I2 tubes. For example, the PVS-15 series of binocular NVG has a 40 degree FOV with an on optical axis resolution of 1.3 cycles/milliradians (mRad).